Suspect Arrested in New York Pharmacy Killings

A suspect in the slayings of four people during the robbery of a New York pharmacy -- a shooting the county police chief called the "most heinous" crime he's ever seen -- was arrested today and is being questioned by police, sources told ABC News.

The suspect was identified as 33-year-old David Laffer. He was picked up at a home this morning just minutes away from where the bloodbath took place.

A team of prosecutors and investigators in the New York City Office of Special Narcotics tracked down Laffer using a prescription database that showed he had filled several prescriptions for hydrocodone at the store where the shootings took place, sources told ABC News.

A woman believed to be the suspect's wife is in protective custody while police determine if she played any role in the robbery, whether she harbored a fugitive or if she is a potential witness.

Police are trying to match Laffer's fingerprints against any prints at the crime scene and a search warrant has been issued for Laffer's home.

The boyfriend of one of the shooting victims was outside the pharmacy when the shootings took place and may be asked to identify the gunman, sources said.

The crime stunned the New York suburb of Medford, on New York's Long Island, and outraged veteran law enforcement officers.

Suffolk County Police Commissioner Richard Dormer called it "one of the most heinous, brutal crimes we have ever encountered."

The quadruple murder was the worst slaying in Suffolk County since the "Amityville horror" in 1974 when Ronald DeFeo killed six members of his family while they slept.

Laffer allegedly walked into Haven Drugs in Medford a little after 10 a.m. on Sunday morning. He shot all four victims execution style and stole a backpack full of prescription painkillers.

"It was a question of going in there and getting oxycontin and getting out of there," Wally Zeins, a former New York Police Department detective, told ABC News.

Suspect in Custody for Bloody New York Pharmacy Shooting

When news of the drug story slaying broke, the detail that the killer stuffed his backpack with painkillers stood out to narcotics investigators.

A team of prosecutors and investigators at the New York City Office of Special Narcotics went to a prescription drug database they maintain where they found that Laffer had filled numerous prescriptions for hydrocodone, the generic for Vicodin and other drugs at the drugstore where the robbery took place, sources told ABC News.

He also lived in Medford near the pharmacy. And he had a pistol permit.

At that point, investigators pulled Department of Motor Vehicles records, got the suspect's photos and compared them to surveillance video, a source said.

Special Narcotics Prosecutor Bridget Brennan brought the information to the New York City prosecutor's federal partner at the Drug Enforcement Administration who brought it to Suffolk County, leading detectives their to the suspect.

Surveillance video taken at the store showed the suspect leaving calmly after the bloody rampage.

Mejia was set to graduate from Bellport High School and Tacetta was planning her fall wedding. Her family intends to bury Tacetta in her bridal gown.

Since the killings, police have urged pharmacies in the area to increase their security. Drug stores are now equipping themselves with surveillance cameras to protect themselves from possible break-ins.

Haven Drugs had been robbed three times over the past 19 months. Long Island has seen a 125 percent increase in hold-ups in the last two years.

"When something like that happens, I don't think any place is safe," Norma Fahel, manager of Beacon pharmacy in Port Washington, N.Y., told ABC News.